The Prince will officially open the second phase of The Alnwick Garden, in Alnwick, Northumberland, which includes the UK’s only public poison garden, growing plants such as cannabis and coca under lock and key.
Earlier in the day, Charles will visit Alnwick Castle, where he will present the country’s only Territorial armoured reconnaissance regiment with its first consecrated flag.
The first phase of The Alnwick Garden, which has cost £35.1 million ($A82.04 million) to construct, was officially opened by the Prince in October 2002.
This afternoon, he will view the second phase of the project, which also contains the world’s largest wooden tree house, a unique set of water sculptures that combine physics with the arts and an imposing pavilion designed by architect Sir Michael Hopkins.
In the morning, Charles will present The Queen’s Own Yeomanry Regiment with its first regimental guidon – a flag of crimson silk damask embroidered and fringed with gold, with the regimental battle honours emblazoned upon it and the regimental emblem embroidered in the centre.
The Queen’s Own Yeomanry is a formation reconnaissance regiment in the Royal Armoured Corps and was formed in 1971.
It is made up of five sabre squadrons administered from a regimental headquarters in Newcastle-upon-Tyne.
In his role as patron of the Prince’s Trust, Charles will also meet Prince’s Trust volunteers from the North East.